INFECTIOUS OUTBREAKS
| ADVANCED INFECTIOUS DISEASE TOPICS —David J. Karras, MD, Professor and Associate Chair for Academic
Affairs, Department of Emergency Medicine, Temple University School of Medicine, Philadelphia, PA
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| Introduction: in 1950s—modern antibiotics introduced (today, still same classes of antibiotics and same mechanisms
of action); vaccines invented; public sanitation and science of clinical epidemiology developed and flourished;
public health agencies well funded; science of disease prevention national priority; modern food-processing
techniques developed; era of complacency followed by era of plagues; inevitable that new pathogens would emerge
and that existing pathogens would develop resistance to multiple drugs; technologic advances made rapid transit of
people possible (allowed diseases to flourish); role as physicians and consumers contributed to development of era
of plagues (eg, negligence in use of antibiotics, abuse of antibiotics by physicians and patients); today — complacency
has led to high-risk behaviors; World Health Organization (WHO) states that threat of serious global pandemic
with profound worldwide human devastation more significant now than at any point in history; question not
whether major pandemic will occur but when
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| Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA): patients describe as “spider
bite” (necrotic eschar growing on top of large abscess); nosocomial infection; prevalence—seen in recently hospitalized
patients, those in long-term care facilities, those previously on antibiotics, those with intravenous (IV) drug
abuse, and those with chronic diseases; increasing rate of MRSA first reported in 1998; several outbreaks reported
since (eg, day care settings, among football players, wrestlers, prisoners); necrotizing fasciitis and pneumonia in
healthy individual associated with CA-MRSA reported; study showed that in emergency department (ED) population,
rate of CA-MRSA among patients with abscesses 55%, and approaching 60% in those with skin and soft tissue
infections; risk factors—black ethnicity (slightly increased risk); history of MRSA or close contact with
individual with MRSA (significant); treatment—no susceptibility of CA-MRSA to first-generation cephalosporin;
clindamycin, trimethoprim–sulfamethoxazole (TMP–SMZ), rifampin (as adjunct to TMP–SMZ), and doxycycline
presently used; at speaker’s institution, clindamycin no longer “go-to drug”; misconception that antibiotics routinely
indicated for uncomplicated abscesses (treatment incision and drainage); no data that adding antibiotics to
uncomplicated abscess beneficial (increases risk for future multidrug-resistant infection); speaker recommends following
patients closely with routine wound checks and culturing uncomplicated infections (to guide therapy and
determine resistance patterns in own institution); when antibiotics necessary (ie, in complicated infection, infection
associated with cellulitis, and when patient not improving) and institution has low prevalence of CA-MRSA, can
still use past antibiotic regimen (eg, cephalosporin); in areas with high MRSA prevalence, particularly those with
high ratio of ethnic minorities, in inner-city area, or area in which individuals exposed to other patients on antibiotics
or who have infections, use appropriate antibiotics; no resistance to linezolid (expensive); TMP–SMZ effective
with nearly 100% sensitivity (can add rifampin); doxycycline fairly effective (88%-92% sensitivity; inexpensive);
resistance starting to develop to clindamycin; vancomycin first-choice drug; cellulitis—misconception that it is
same as abscess; Streptococcus pyogenes more common in cellulitis than in abscesses; TMP–SMZ generally inadequate
for streptococcal infections; treatment options include adding first-generation cephalosporin; can use cephalexin
alone if treating uncomplicated cellulitis; amoxicillin–clavulanic acid (Augmentin) still recommended; more
resistance to macrolides seen (no longer recommended); penicillin effective if treating erysipelas on face and extremities
(almost always S pyogenes)
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| Drug-resistant urinary tract infections (UTIs): uncomplicated UTIs (ie, cystitis and uncomplicated pyelonephritis)
usually associated with Escherichia coli, sometimes Staphylococcus; ampicillin no longer used because almost
50% of E coli in uncomplicated infections resistant; national data show almost as many patients resistant to cephalexin
(Keflex) and 20% resistant to TMP–SMZ; federal government recommends resistance ceiling of 20% for use
of antibiotic in uncomplicated infections; ciprofloxacin has 5% to 10% resistance (levofloxacin same); third-generation
cephalosporins highly effective if given IV; nitrofurantoin (eg, Macrobid) has virtually no resistance;
fluoroquinolones—still drug of choice, with no treatment failures to date; shorter course of therapy advantageous
for patients with pyelonephritis; choices include ciprofloxacin, ofloxacin (no significant advantage, more expensive),
and levofloxacin (better prostate penetration); moxifloxacin (eg, Avelox) and gemifloxacin (Factive) not indicated;
nitrofurantoin—excellent for uncomplicated cystitis but no coverage against other pathogens
(complicated infections); because of inability to reach effective serum concentrations, not indicated in sepsis or in
pyelonephritis; TMP–SMZ—determine resistance for E coli in own institution; inexpensive; appropriate for patient
with no risk factors for complicated infection, not recently on antibiotics, young, and not sexually active; even
if culture shows resistant organism, if patient improving, speaker would not switch to different drug; no longer any
indication for single-dose therapy for any UTI; shortest course of therapy possible for uncomplicated cystitis 3
days; although more expensive, ciprofloxacin more cost-effective (shorter course of therapy with higher cure rate);
patient hospitalized for UTI presumably bacteremic, therefore necessary to use drug with adequate serum level (ie,
third-generation cephalosporin)
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| Diarrhea: second most common cause of lost days from school and work (most common viral illness); half-billion
episodes annually in United States; causes 3000 deaths annually, 300 of whom are children <5 yr of age; E coli
O157:H7—found in hamburger, raw milk, and at petting zoos; exists in intestines of ≈50% of cattle in United
States; in meat processing plant, spillage of entrails from just one cow with E coli can contaminate 25,000 pounds
of hamburger; also seen in dried fermented salami, unpasteurized apple juice and cider, and raw vegetables; starts
with diarrhea that becomes grossly bloody 2 to 3 days later; hemolytic uremic syndrome (HUS)—complication
seen in 10% of patients; leading cause of renal failure in children; more likely in very young or very old patients;
patient with grossly bloody stools with severe cramps but no fever at high risk for diarrheal illness that leads to
HUS; patients with E coli infection given antibiotics at 14 times greater risk of developing HUS than those not
given antibiotics; also true in those given antidiarrheals compared to those not given; study showed ≈3% of patients
who presented to ED with bloody diarrhea had E coli O157:H7 or similar type of infection; studies show E coli
O157:H7 infections implicated in 1% to 5% of all diarrheal illnesses presenting for medical care; several studies
show that patients with diarrhea given antibiotics improve faster, whether bacterial or viral infection present,
whether heme-positive stool present, and whether positive cultures present; no study has shown treatment with antibiotic
induces Salmonella carrier state (not studied in children); latest guidelines from Infectious Diseases Society
of America state that antibiotics appropriate if used by adult with moderate to severe illness (ie, experiencing moderate
to severe cramps and fever and incapacitated by disease), particularly with heme-positive stools and acute disease;
treatment—fluoroquinolones recommended (ciprofloxacin bid or levofloxacin daily); TMP–SMZ still
effective; macrolides no longer effective; single dose of these drugs just as effective as 3-day course; if patient recently
on antibiotics or hospitalized, potential for Clostridium difficile (add metronidazole [eg, Flagyl] if patient
treated empirically); do not use antibiotics—if E coli 0157:H7 suspected (patient has grossly bloody diarrhea, severe
cramps, and no fever) or known outbreak present; no benefit from antibiotics if patient has mild disease (almost
always viral); if longstanding symptoms present (probably not infectious and requires culture and work-up);
in children and immunocompromised patients
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| Avian influenza: influenza A H5N1; avian flu advisory stated that if United States has moderate outbreak (similar
to 1958), expect 90 million Americans to have avian flu (≈30% of population); ≈50% treated as outpatients, ≈1
million people would require hospitalization, ≈28,000 would need to be in intensive care unit, 65,000 would require
ventilators, and 200,000 would die; if outbreak severe, ≈2 million deaths; WHO places at bioterrorism level
3 (no evidence of human-to-human transmission); preventive measures (eg, providing disposable napkins in waiting
room, handwashing) advocated by Centers for Disease Control and Prevention (CDC) to prevent spread of epidemic
flu; triage recommended by CDC and shortly by Joint Commission on Accreditation of Healthcare
Organizations (JCAHO) to identify individuals at high risk of spreading epidemic flu (ie, those who have fever,
have respiratory complaints, have recently traveled to area with known epidemic flu activity or have been exposed
to individual who has recently traveled to epidemic area, or have high-risk occupation); if individual meets
high-risk criteria, he or she should be isolated in negative-pressure room; maintain respiratory isolation when patient
in treatment area; also necessary to perform influenza A test and, if positive, patient should be maintained in
isolation throughout hospital stay; necessary to report case to CDC and consider initiating therapy (eg, oseltamivir
[Tamiflu]); protective measures—frequent handwashing; using N95 respirator and maintaining contact isolation
with gloves and protective gown when dealing with patient who has, or is suspected of having, epidemic flu; dedicated
equipment, eg, disposable single-use stethoscopes and blood pressure (BP) cuffs; anti-influenza therapy if
exposed to patient with avian flu; oseltamivir—effective; decreases risk of developing influenza by 75%; Measure
PN-5b—measure by JCAHO and Center for Medicare and Medicaid Services (CMS) that assesses percentage
of patients with pneumonia in ED who receive antibiotics within 4 hr of arrival; national performance
standard; publicly reported information; tied to reimbursement; based on article in JAMA that showed better outcomes
of treatment of pneumonia in elderly patients if treated within 8 hr (same guidelines from American Thoracic
Society); another study reported better outcomes if patients treated within 4 hr; however, 4-hr cutoff
arbitrary; after 8 hr, mortality increases; speaker theorizes that poor outcomes associated with delayed recognition
and treatment of pneumonia; goal of guideline to improve overall quality of care; dangerous to comply with measure
by providing patients with antibiotics at triage (before chest x-ray results known)
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| PETS IN THE HOSPITAL SETTING —Terry Yamauchi, MD, Professor of Pediatrics, University of Arkansas for
Medical Sciences College of Medicine, and Chair, Infection Control, Arkansas Children’s Hospital, Little Rock
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| Pet therapy or animal-assisted therapy: emerging in extended care facilities, facilities for mentally ill, developmentally
disabled, and long-term care, and children’s hospitals; benefits include improved mental health by enhancing
wellness; measures of improved mental health include, eg, decrease in use of pain medications in
children with sickle cell crisis; in adults or elderly, decrease in BP and heart rate; animal-assisted therapy program
should ensure that all patients, hospital employees, and visitors protected; speaker’s study—cultures taken
from animals in petting zoo; found that some animals became culture-positive after visiting hospital (brought
about by stress); in another study by speaker, cultures taken from ≈40 animals (dogs and cats) that were not ill,
had no sores, were not on any antibiotic for ≥30 days, were primarily house pets, and had no household members
who were medical personnel; found Staphylococcus, Group A Streptococcus, Salmonella, Pasteurella, and
MRSA; conclusion that nonsick dogs and cats (primarily house pets) could carry pathogens; in later study by
speaker, cultures taken from more dogs and cats and all individuals who participated in study; all 42 animals colonized
with S aureus, with 16% (n= 7) MRSA; look for MRSA if considering using animals in therapy program;
assess risk vs benefit; speaker concerned about liberal policies allowing animals in hospital
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Suggested Reading
Dundas S et al: Using antibiotics in suspected haemolytic-uraemic syndrome: antibiotics should not be used in Escherichia
coli O157:H7 infection. BMJ 330:1209; author reply 1209, 2005; Fee C et al: Identification of 90% of patients
ultimately diagnosed with community-acquired pneumonia within four hours of emergency department arrival
may not be feasible. Ann Emerg Med 49:553, 2007; Goicoechea M: Human H5N1 influenza. N Engl J Med
356:1375; author reply 1376, 2007; Gupta K: Addressing antibiotic resistance. Dis Mon 49:99, 2003; Hayden FG:
Antiviral resistance in influenza viruses--implications for management and pandemic response. N Engl J Med
354:785, 2006; John CC et al: Therapies and vaccines for emerging bacterial infections: learning from methicillin-
resistant Staphylococcus aureus. Pediatr Clin North Am 53:699, 2006; Johnigan RH et al: Community-acquired methicillin-resistant
Staphylococcus aureus in children and adolescents: changing trends. Arch Otolaryngol Head Neck
Surg 129:1049, 2003; Ladhani S et al: Increasing antibiotic resistance among urinary tract isolates. Arch Dis Child
88:444, 2003; McFee RB: Global infections--avian influenza and other significant emerging pathogens: an overview.
Dis Mon 53:343, 2007; Miller LG et al: Treatment of uncomplicated urinary tract infections in an era of increasing
antimicrobial resistance. Mayo Clin Proc 79:1048, 2004; Moellering RC Jr: The growing menace of community-acquired
methicillin-resistant Staphylococcus aureus. Ann Intern Med 144:368, 2006; Razzaq S: Hemolytic uremic
syndrome: an emerging health risk. Am Fam Physician 74:991, 2006; Werber D et al: Shiga toxin-producing Escherichia
coli O157 more frequently cause bloody diarrhea than do non-O157 strains. J Infect Dis 189:1335, 2004.
Educational Objectives
| The goal of this program is to improve the management of infectious diseases and to explore the possible dangers of
pet therapy in health care facilities. After hearing and assimilating this program, the clinician will be better able to:
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 | 1. Discuss the reasons for the emergence of new pathogens and the development of drug resistance by existing
pathogens.
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| 2. Prescribe the appropriate antibiotic for community-acquired methicillin-resistant Staphylococcus aureus and
drug-resistant urinary tract infections.
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| 3. Recognize diarrhea caused by Escherichia coli O157:H7 and how to treat it.
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| 4. Utilize recommended preventive measures for avian influenza.
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| 5. Consider the potential dangers of pet therapy in health care facilities.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and planning committee
members to disclose relevant financial relationships within the past 12 months that might create any personal conflicts
of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in
health care and not a proprietary business or commercial interest. For this program, the following has been disclosed:
Dr. Yamauchi is on the Speakers’ Bureaus of Abbott Laboratories and Merck. Dr. Karras and the planning committe
reported nothing to disclose.
Acknowledgments
Dr. Karras was recorded at the 2007 Annual Scientific Assembly, held April 10-12, 2007, in Philadelphia, PA, and
jointly sponsored by the American College of Emergency Physicians and the Pennsylvania Chapter, American College
of Emergency Physicians. Dr. Yamauchi was recorded at the Symposium on Critical Care and Emergency Medicine
, held March 29-31, 2007, at Hot Springs, AR, and sponsored by the University of Arkansas for Medical
Sciences College of Medicine and the University of Tennessee Health Sciences Center College of Medicine. The Audio-Digest
Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.
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